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December 19, 2016
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October 11, 2005
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September 18, 1953
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Approved For Release 2005/12/01 : CIA-RDP80-0081OA002200140053-4 CENTRAL INTELLIGENCE AGENCY INFORMATION REPORT This Document contains information affecting the Na- tional Defense of the United States, within the mean- ing of Title 18, Sections 793 and 794, of the U.S. Code, as amended. Its transmission or revelation of its contents to or receipt by an unauthorized person is prohibited by law. The reproduction of this form is prohibited. SECRET/CON'T OL.US OFFICIALS ONLY SECURITY INFORMATION COUNTRY USSR (Kalinin Oblast) SUBJECT Development of the DFS-301 and DFS-346 Aircraft Types at Zavod Noe 1 Podberezye 25X1 25X1 DATE DISTR. NO. OF PAGES REQUIREMENT REFERENCES 25X1 18 September 1953 4 25X1 to Plant No. 1 (Zavod 1) in.Podberezye had a workforce of about 1000 persons,, including 250 to 300 who worked at ORB I, about 220 at OKB II, and 450 to 500 Soviets. There were about 1,800 German engineers and dependents in Podberezyeoi Except for individual departments which occasionally worked in two shifts, work was done eight-hour shift. 2a The original DFS,-346.airframe, constructed at Halle, was heavily damaged duripg the transport and was, therefore, used only for ground tests with.high-frequency instruments. 30 A remodeled Kranich-type (sic) glider served Wolfgang Ziese as a trainer for flying in prone position. For safety reasons, a second pilot was sitting be- hind Ziesee DFS 01 4. The second test model constructed for the development of the DFS-346 was the DFS-301 without power unite Measuring equipment, including three string oscillographs, two batteries, one master compass for inductance indication, two modified turn and bank indicators which served as angular velocity meters. and two altitude recorders, was _ installed .in? .the rears. of the plane.. A quadruple indicator for angle of incidence and for the angle of sideslip besides ; voice radio. connection to the Tu-2 towing aircraft and to the ground station ..s in- stalled in the pilot's cabin. The entire measuring equipment had been developed and constructed at Dr. Wede1s (Wehrle) (fnu) office. The figures obtained by the osciilogrephs.were evaluated by Erich Steeko 5. The construction. of the DFS-301 was started in Podberezye in late March 1947 and the plane was completed by early July 1948? The plane was immediately trans- ferred to Moscow/Salarevo (Teplyy Stan) where it was rigged and where the wings were mounted, etc. The aircraft made its first satisfactory test; flight SECRET/CONTROL US OFFICIALS ONLY (Note: Washington Distribution Indicated By "X"; Field Distribution By "#".) Approved For Release 2005/12/01 : CIA-RDP80-0081OA002200140053-4 Approved For Release 2005/12/01 : CIA-RDP80-0081OA002200140053-4 ECR.EP/C0 R.OL US OFFICIALS OULY I about 15 August 1948. Then the plane was accep ed by the Soviet dontrol commission (O'TK Otdel Tekhnicheskogo Kontrolaf who?for three or four days, until about 20 August 1948, checked the W-301, and installed and. sealed.the ejector charge (cartridge) which was to effect the launching of the plane by disconnecting the pipes to release compressed air to the catapult cylinders. The cartridge was removed in the evening of every flying day and reinstalled in the morning. 6. After the first testing program, which included about ten flights and lasted from 20 August 1948 to April 1949, was finished, the aircraft was subjected to several modifications, K e. boundary layer (fences were mounted) on the wings and the elevator assembly. During these tests the rigid outrigger skids under the wing tips were replaced by larger elastic ones which had been copied from the supporting skids of the Lilly (EF-126), or were dismantled from the Lilly and remodeled for use with the DFS-301. The second testing; program included about 20 flights and lasted from July to December 1949. 7. The following modifications were made on the DFS-301 between the first and second flight testing programs: Boundary layer fencesaconstructed at Zavod 1, were fitted to the plane after the first flight of the second test program. Three fences were fitted to each. wing,-bue'70-fo 80 cm from the fuselage, one about one meter from the wing tip and the third one in the center between the other -two. One boundary layer fence was the under-side of the elevator assembly on either side of the'aircraft. The installation of the boundary layer fences had been suggested by the TsAGI Institute. The ex- tending mechanism of the main landing skid was at first operated by means of a handOlever, ratchet, and spindle, with a bicycle chain used as trans- mission between ratchet and lever. This mechanism was replaced by a hydraulic system, since .too much time was required for the extending procedure. This modification was also prepared at Za:vod. 1 and the hydraulic system was in- stalled at Tep.lyy Stan by mechanics of the Zavod 1 assembly department. The modification work lasted from mid.-May to early June 1949. Holding devices for the lead blocks, which were to function as counterbalance to the engine, were fitted to the last bulkhead in the tail of the plane, directly under the elevator assembly. On Ziese?e request, a loop antenna was installed and the arrangement and holding device of the antenna mast was modified, because the original arrangement was too flexible and proved, liable to flutter. A. window was in each side of the fuselage behindthe pilot, so he was able to look at the wings. On suggestion of the aerodynamic experts at OXB II, each wing was lengthened by about one meter. However, the flight, performance of the plane was not improved by this modification and after two test flights the wings were reduced to their previous length. In accordance with the ex- periences gained with the D!FS-301, the wings of the DFS-346 were not lengthened. All modifications were completed by the end of June 1949. 8. The first flight test program, which was to reveal the flying performance of the D'FS-301 at ballast flights with different quantities of water in the fuel tank, revealed exceptionally good aerodynamical properties of the plane. De- tails on the individual test flights could not be given. 25X1 a maximum speed of 500 km/h was allegedly reached during these tests. 9. During the second flight test program the "OFS-301 was flown with lead ballast and with the measuring equipment in the fuselage container in operation.. Flights at an inciinpd angle of the path were allegedly flown at V max 750 km/h (maximum path speed). The twelfth through fifteenth flight tests were flown with wooden wings, which were constructed, in Moscow. However, Exenty during the first flight, these wooden wings vibxs,ted so villent,ly that the connecting bushings were deformed to oval, shape. The bushings had to be ground and the bolts had 25X1 to be provided with chromium plating. these wings were very poor in quality; particularly the glued joints were very defective. Between the first and second test flights with the wooden wings the aircraft was checked by the control commission and was released for further test flights after the bushings and bolts were overhauled. After the third test flight the wooden wings were finally dismantled and the project was never mentioned again. SECFET/COITTFOL US OFFICIALS ON1'.;Y Approved For Release 2005/12/01 : CIA-RDP80-0081OA002200140053-4 Approved For Release 2005/12/01 : CIA-RDP80-00810A002200140053-4 SECEET/Cc TROL .uS OFFICIALS ONLY -3- 25)(1 25X1 25X1 the flying performance of the DFS-301 during the second test was excellent. The boundary layer fences, the modifications of the . program extension mechanism of the main landing gear skid, the remodeled outrigger skids, as well as the measuring equipment, be a-successes Aerobatics were not included in the testing programs. It was difficult to get the DFS-301 spinning. In stall condition, the aircraft vibrated and then leaned over to the noses seldom flown an aircraft of such excellent stability. All modific.;tions experienced with the DFS-301 were utilized for the design of the DFS-3)460 Furthermore, the PPS-346 was equipped with an ad- justable elevator assembly, with limit switch which was to be controlled by an electrically operated spindle, because the control pressure of the DFS-301 was apparently too strong. The electric motor used for this control system. was i9.20O'$ att flywheel starter engine, 'hich was to drive the spindle via a transmissions The shoes of the pedal operating the vertical rudder had also to be modified, becauserF- when catapulting out one might get stuck with the tip of the foot. Another modification accomplished on the DFS-346 on the basis of the experiences with the the IFS-301 was the locking device of the canopy which, with the DFS-301 could only be opened from the.outside by means of a bowden cable through a hand flap. The canopy of the DFS-346 could be opened by the pilot from insides 110 After the second test program was completed, the DFS-301 was covered with tarpaulins and sealed and remained at `Tep.l.yy Stan.n became of the aircraft o It was not known what DFS 146 12 0 25X1 25X1 130 25X1 The flying program with engines was to start in spring 19510 25X1 r DeTlovou Q , MIUKC September 1950, the aircraft was not subjected to Hy modifications Three identical test models of the DFS-3146 were simultaneously under con- struction. Work on the wings and the fuselages was started in about September 1948, while the assembly of test model No. 3 was started by January 1949, and completed by late February 1949. In early Mbarch, test model No 0 2 was sub -- jected to vibration tests. The plane, suspended from rubber ropes, had a Leonard engine installed in. the wings o '.'h.ese tests lasted about, two weeks and terminated between 20 and 25 March0 Testing had to be done at night, because during the day the electric current was too weak or failed completely. Ac- cording to the experiences gained in the vi'bration tests, the bulkhead in the fuselage, about 20 cm. behind the leading edge of the wing, had to be reinforced. Further modifications on fuselage and wings were not necessary. The model was then transferred to Teplyy Stan for t,vests q with lead ballast in the tail and a Tu-4 acting as tow-plane. This test program. was continued until July 19500 The model was then returned to Zavod 1 and parked in a hangar. 25X1 001g nnnp~yarp the ski6s of nta, model Nos of the D'FS- 46 damaged, e and. landed outside of the Experimental model woe was comp le eight to ten days later than :boa 3. After the airframe had been assembled the engine was installed. Including the density tests for the pipes and containers, this procedure. required 'two days. Then the wings were dismantled again and the fuselage with engine was shipped to the engine test stand of Zavod 1 for static thrust tests, etc e The tests lasted two weeks and were completed by late March 1950. Then the wings were packed. in canvas-covered crates and the fuselage was covered with tarpaulins and sealed by the control commission. The aircraft 'was ,ready to be shipped to another airfield because Teplyy Stan airfield beca;ne boggy in rainy weather, and the landing on steel matting seemed too-dangerous meat; Bans Motech, as flight administrator; Erhardt Sczuka, as chief mechanic; and an undetermined engineer from. -the Mantey Group. During summer 1950, ex- perimyntal model No. 1 way assembled in the same way as the other two models,. tested at the engine test stand, and stored as a reserve. The testing team was to include Ziese; Erich Steek, for the measuring equip- SECRRT/COUTROL US OFFICIALS Mlzrf Approved For Release 2005/12/01 : CIA-RDP80-00810A002200140053-4 Approved For Release 2005/12/01 : CIA-RDP80-00810A002200140053-4 SEM.TJ 0NTR.OD . US OFFICIALS ONLY O 25X1 A- 14. For test flights, the DFS-346 was towed by a `.''u-+ which climbed to any altitude of about 10,000meters, from where the DFS-34+6 was catapulted to glide down. 15. The power unit for the IMPS?3l6, assembled at the engine department under the supervision of Kurt Schell and Herbert; Ufer, absolved its State test in January 1950. By this time, three complete double-engines had been completed. Each double-engine reached a, total output of 3,000 to 3,500 kgp, but never 4,000 kgp. The double engines were fueled with "T-Stoff" and "C-Stoff" and included nine steps. Each engine could also be operated individually. The pumping turbine rotated at 18,000 to 24,000 rpm. The longest test run lasted 2.5 minutes. The containers for the T and C-Stoff were pure aluminum. Dr. Wede's Office 16. The office and laboratory headed by Dr. Wede (fau) manufactured instruments for the test flight program, suchas9 measuring instruments for angles of incidence, angles of side slip, acceleration meters, extensometers, and tension indicators. Up to about 30 extensometers and tension indicators had to be manufactured for the TsAGI Institute per month. Also other instruments of this kind had to be continuously delivered in small, series to TsAGI and ,other Soviet offices. These instruments had first operated with potentiometers functioning as pickoffs; however, because of the difficulties encountered in the supply of wire,, they were converted to operate on an ind?.ction basis. The instruments were packed 25X1 in boxes and picked up by officers who arrived in sedans. 25X.1 25X1 1. commmentt 0PN 'o. a a workforce of about 500 German experts and about 25X1 3D5O3 Soviets. Also Othe German group with dependents included about 25X1 1,500 persons. 25X1 2, C The English translatioL, for tIK is Technical Control sec t, ora' SBG,R t/COM ROL, US O,F;FICIATS o;NIY Approved For Release 2005/12/01 : CIA-RDP80-00810A002200140053-4